The present invention relates to a database management technique, and in particular, to a technique to manage a database resource when a program is activated according to a processing request to execute database processing.
A database language “structured query language (SQL)” has a function to call, as a routine, functions and procedures defined by a user. The functions and the procedures are analyzed when the routine is defined, and are registered to a database management system (DBMS) as an execution module related to a routine name. An execution module is produced as follows. A sequence of database processing procedures are analyzed to be converted into a format executable in the database management system. An execution module is also called “execution plan”. When a routine call is issued and a routine name specified as information of the routine call, database processing is executed according to an execution module registered in association with the routine name.
On the other hand, an article “SQLJ-Part 1: SQL Routines using the Java Programming Language, SIGMOD Record, Vol. 28, No. 4, December, 1999” describes a function to execute, as a routine, a program written in the Java programming language. Java is a trademark or a registered trademark of Sun Microsystems, Inc. of the United States.
In this function, when a routine is defined, a program is registered in association with a routine name. In a routine call, a database management system executes a program in a program execution environment. When an SQL statement is issued, the program execution environment calls the database management system, and hence an execution module is generated and database processing is executed.